Adjustable abrasive and dust separator

ABSTRACT

Provided is a centrifuge media separator for separating blast particulate from fine particulate carried by air flowing from a blast cabinet and through the media separator. The centrifuge media separator comprises an upper panel, a lower panel, and an outer wall. The upper panel has a central opening formed therein. The outer wall is configured in a truncated logarithmic shape and which extends between the upper and lower panels. The outer wall has at least one particulate escape aperture formed therein. The upper panel, lower panel and outer wall collectively define a curvilinear air passageway having an inlet and an outlet. An air foil extends from the outer wall in to the air passageway. The distance than the air foil extends in to the air passageway is adjustable. The inlet is configured to allow a flow of air to enter the air passageway and circulate therethrough toward the outlet. The escape aperture is configured to exhaust the blast particulate out of the passageway. The central opening is configured to exhaust the fine particulate out of the passageway.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 15/858,919, filed Dec. 29, 2017, the entiredisclosure of which is expressly incorporated herein by reference.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND

The present invention relates generally to blast cabinets and, moreparticularly, to a uniquely configured centrifuge media separator thatmay be included with the blast cabinet and which is specifically adaptedto separate blast particulate of various masses from fine particulatesuch that the blast particulate may be recycled through the blastcabinet while the fine particulate may be removed from the blast cabinetin order to improve the visibility of a workpiece being blasted withinthe blast cabinet.

Blast cabinets are typically utilized to clean or generally preparesurfaces of a workpiece by directing high pressure fluid containingabrasive blast media or blast particulate toward the workpiece. Theabrasive blast particulate is typically a relatively hard material suchas sand, sodium bicarbonate (i.e., baking soda), metallic shot or glassbeads although many other materials may be selected for use as the blastparticulate. These media may have differing masses, and thereforediffering momentums when moved by an air flow of a given velocity. Theblast cabinet typically includes a housing supported on legs. Thehousing defines a generally air tight enclosure having a pair of armholes with gloves hermetically sealed thereto such that an operator maymanipulate a blast hose and/or the workpiece for blasting thereof withinthe enclosure. The blast hose is configured to direct the high pressurefluid such as air carrying the blast particulate at high velocity towardthe workpiece surfaces. The blast cabinet typically includes atransparent window to allow the operator to manipulate the workpiece andto visually observe the progress of the blasting.

During blasting, the blast particulate bounces off of the workpiece andis generally violently thrown about within the enclosure such that aportion of the blast particulate normally breaks down into smallerdust-like particles hereinafter referred to as fine particulate. Inaddition, surface coatings, dirt and scale that are abraded from theworkpiece by the blast media contribute to the formation of fineparticulate within the enclosure. The fine particulate is too small tobe effective as a blast medium and therefore must be eventually removedfrom the blast cabinet. In addition, the fine particulate is of suchsmall size such that it may be suspended in the air within the enclosureof the blast cabinet. Over time, the gradual buildup of the fineparticulate can create a foggy or clouded environment within theenclosure which visually impairs or obstructs the operator's view of theworkpiece. Due to health and safety regulations and environmentalrestrictions, the particulate-filled air cannot simply be exhausted tothe atmosphere. Rather, the particulate-filled air must be filteredprior to exhaustion in order to remove the fine particulate carriedtherein.

Accordingly, many prior art blast cabinets are ventilated and includefilters such that at least a portion of the fine particulate may bepurged from the air. Prior art cabinets having the capability to purgefine particulate from air prior to its exhaustion out of the enclosurein order to improve the operator's visibility of the workpiece withinthe enclosure have been made. These blast cabinets separate blastparticulate from fine particulate such that the blast particulate may berecycled through the blast cabinet. These blast cabinets alsoincorporate a centrifuge media separator which eliminates the need for afilter.

However, because the differing masses of blast media, the principle ofoperation of the state of the art blast cabinets is such that the blastcabinets work most effectively with higher mass blast media. Cost ofhigher mass blast media may make lower mass blast media more desirable.In addition, environmental regulation of a particular geographiclocation may dictate the use of lower mass blast media. Offering theflexibility for the same blast cabinet to use blast media of differingmasses offers tremendous advantages.

BRIEF SUMMARY

In accordance with the present disclosure, there is provided a blastcabinet for blasting the surface of a workpiece with blast media, theblast cabinet may comprise a housing, and blast media placed within thehousing. The blast cabinet may also include a centrifuge mediaseparator. The centrifuge media separator may include a top panel, abottom panel, an inner wall extending downwardly from the top panels,and an outer wall including surrounding the inner wall and extendingbetween the top and bottom panels, the outer wall may define a truncatedlogarithmic spiral. The top panel, the bottom panel, inner wall, andouter wall may collectively define a passageway and a central opening,the passageway may have an inlet and an outlet and a transverse crosssection which may generally decrease from the inlet to the outlet. Thecentrifuge media separator may further have an escape aperture in theouter wall, and an air foil adjacent the escape aperture, the air foilextending from the outer wall in to the passageway a distance, thedistance being adjustable between a minimum and a maximum.

There is further provided in the present disclosure a centrifuge mediaseparator for separating blast media from fine particulate matter whenboth the blast media and fine particulate matter are carried in an airflow. The centrifuge media separator may include a top panel, a bottompanel, an inner wall which may extend from the top panel and maydefining a gap between the inner wall and the bottom panel, and an outerwall which may include an escape aperture. The outer wall may surroundthe inner wall and extend between the top and bottom panels. The outerwall may define a truncated logarithmic spiral. The centrifuge mediaseparator may include an air foil. The air foil may include a leadingedge. The air foil may be attached to the outer wall and the leadingedge may be angled in a direction opposite the air flow to direct aportion of the air flow to the escape aperture. The top panel, thebottom panel, inner wall, and outer wall may collectively define apassageway. The passageway may have an inlet and an outlet, and thepassageway may have a transverse cross section which may generallydecrease from the inlet to the outlet. When the blast media and fineparticulate matter enter the passageway at the inlet, and are carried bythe airflow toward the outlet, the configuration of the passageway maycause fine particulate matter to be closer to the inner wall than theblast media, and the air foil may extend from the outer wall in to thepassageway a distance to intercept the blast media and may direct theblast media to the escape aperture, the air foil may be adjustable tovary the distance between a minimum and a maximum.

There is further provided in the present disclosure a method of forminga centrifuge media separator for separating blast media from fineparticulate matter when both the blast media and fine particulate matterare carried in an air flow. The method may include providing a toppanel, providing a bottom panel, providing an inner wall including a topedge and a bottom edge;

attaching the top panel to the top edge of the inner wall such thatthere is a gap between the bottom edge and the bottom panel;

providing an outer wall including an escape aperture, an upper edge, anda lower edge;

attaching the outer wall so that the outer wall surrounds the inner walland the upper edge attaches to the top panel and the lower edge attachesto the bottom panel, the outer wall defining a truncated logarithmicspiral; and

attaching an air foil to the outer wall, the air foil including aleading edge and adjustment slots, the adjustment slots including afirst end and a second end, and the leading edge being angled in adirection opposite the air flow to direct a portion of the air flow tothe escape aperture;

wherein the top panel, the bottom panel, inner wall, and outer wallcollectively define a passageway, the passageway having an inlet and anoutlet, and a transverse cross section which generally decreases fromthe inlet to the outlet, and the air foil is adjustable from the firstend to the second end of the adjustment slots to move the leading edgefrom closer to the outer wall to further away from the outer wall.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the various embodimentsdisclosed herein will be better understood with respect to the followingdescription and drawings, in which like numbers refer to like partsthroughout, and in which:

FIG. 1 is a perspective view of a blast cabinet having a centrifugemedia separator of the present invention incorporated therein;

FIG. 2 is a perspective view of the centrifuge media separator having aspiral configuration for centrifugally directing blast particulate to anouter wall of the media separator;

FIG. 3 is a perspective view of the centrifuge media separator alongsight line 3 in FIG. 2 , including the air foil placed in the escapeaperture;

FIG. 4 is an exploded detail perspective view of the air foil, escapeaperture, and bracket of FIG. 3 ;

FIG. 5 is a cross sectional view of the centrifuge media separator atthe line 5-5 of FIG. 3 ;

FIG. 6 is a detail view of the air foil, escape aperture, and bracket ofFIG. 5 with the air foil in the maximum position;

FIG. 7 is a detail view of the air foil, escape aperture, and bracket ofFIG. 5 with the air foil in the minimum position;

FIG. 8A is a top cross section view of a centrifuge media separator withan alternative air foil;

FIG. 8B is a detail perspective view of the alternative air foil of FIG.8A;

FIG. 8C is a detail top view of the alternative air foil;

FIG. 9A is a perspective of a centrifuge media separator showing thebottom panel, inner wall, and central opening;

FIG. 9B is a side cross sectional view of the centrifuge media separatorof FIG. 9A;

FIG. 10A is a perspective view of a centrifuge media separator showingthe bottom panel and central opening; and

FIG. 10B is a side cross sectional view of the centrifuge mediaseparator of FIG. 9A.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of certain embodiments of amachining tool assembly for a firearm lower receiver and is not intendedto represent the only forms that may be developed or utilized. Thedescription sets forth the various structure(s) and/or functions inconnection with the illustrated embodiments, but it is to be understood,however, that the same or equivalent structure and/or functions may beaccomplished by different embodiments that are also intended to beencompassed within the scope of the present disclosure. It is furtherunderstood that the use of relational terms such as first and second,and the like are used solely to distinguish one entity from anotherwithout necessarily requiring or implying any actual such relationshipor order between such entities.

Referring to FIG. 1 , shown is the blast cabinet 10 including acentrifuge media separator 30 incorporated therein. The blast cabinet 10may be comprised of a housing 48 supported on legs 46. A section of thehousing 48 may have a generally inverted pyramid shape such that spentblast particulate 18 may be funneled downwardly toward a lower portionof the housing 48 and subsequently picked up by the high pressure source(not shown) for recycling through the blast cabinet 10. The housing 48has a generally air tight enclosure 12 with arm holes 26 to which twohermetically sealed gloves 14 may be attached. The housing 48 alsoincludes a transparent window 16 such that an operator may reach thoughthe arm holes 26 to grasp and/or manipulate the workpiece 24 duringblasting thereof with the pressure hose.

The housing 48 of the blast cabinet 10 may also include at least onedoor allowing access into the enclosure 12 such that the workpiece 24may be inserted therein and removed therefrom. The pressure hose is aconduit for a high pressure, high velocity fluid. The fluid acts as acarrier medium and carries blast particulate 18 for high velocitydischarge onto surfaces of the workpiece 24 in order to remove coatingsfrom or otherwise prepare the workpiece 24 surfaces, as will bedescribed in greater detail below. The fluid may be a gas such as air asmay be utilized in the blast cabinet 10 of FIG. 1 . However, the fluidmay also be a liquid such as water. While the specific construction ofthe blast cabinet 10 is as shown in FIG. 1 , it should be noted that thecentrifuge media separator 30 may be utilized or incorporated into blastcabinets 10 and other similar devices of differing configurations.

The media in the blast cabinet 10 is generally comprised of blastparticulate 18 and fine particulate 20. Although the mass of the blastparticulate 18 may vary between lower and higher masses, the centrifugemedia separator 30 separates the blast particulate 18 from the fineparticulate 20 in order to purge the fine particulate 20 from aninterior of the blast cabinet 10 so as to increase the visibility of aworkpiece (not shown) being blasted by a pressure hose (not shown)within the blast cabinet.

As shown in FIGS. 2-5 , the centrifuge media separator 30 may bespecifically configured to separate blast media. To achieve theseparation of the blast particulate 18 and the fine particulate 20 theouter wall may include an escape aperture 44 which may operate incombination with an adjustable air foil 50. The air foil 50 may direct aportion of the high pressure, high velocity fluid toward the escapeaperture 44. The portion of the high pressure, high velocity fluid beingdirected toward the escape aperture 44 may be controlled by adjustingthe air foil as is described in greater detail below.

A portion of the high pressure, high velocity fluid may carry blastparticulate 18. Another portion of the high pressure, high velocityfluid may carry fine particulate 20. The air foil 50 may be adjusted inthe direction indicated by the arrow in FIG. 3 , so that the portion ofthe high pressure, high velocity fluid carrying the blast particulate 18may be directed by the air foil 50 to the escape aperture 44 to enableseparation of the blast particulate 18 from the fine particulate 20.Separation of the blast particulate 18 from the fine particulate 20allows for reclaiming or recycling of the blast particulate 18 throughthe blast cabinet 10 in order to lower operating costs.

As shown in FIGS. 2 and 3 , the centrifuge media separator 30 mayinclude a top panel 54, a bottom panel 56, an inner wall 42, and anouter wall 40. The outer wall 40 may extend between the top and bottompanels 54, 56, and this orientation creates an outer surface and innersurface of the outer wall 40. The outer wall 40 may surround the innerwall 42. The inner wall 42 may include a top edge and a bottom edge. Thetop edge may be attached to the top panel 54, such that the inner wall42 extends partially downwardly from the top panel 54. The bottom edgeof the inner wall 42 and the bottom panel 56 may define a gap. In thisregard, the inner wall 42 may extend downwardly about one-quarter toabout one-third of an overall height of the centrifuge media separator30 although the inner wall 42 may extend downwardly in any amount. Theinner wall 42 further defines a central opening 36 in the top and bottompanels 54, 56. The overall height of the centrifuge media separator 30is defined by a distance between the top and bottom panels 54, 56. Byincluding the inner wall 42 with the centrifuge media separator 30, theoperating efficiency thereof may be improved.

Alternatively, as shown in the centrifuge media separator 30 of FIGS. 9Aand 9B, the bottom edge of the inner wall 42 may be connected to thebottom panel 56. When the bottom edge of the inner wall 42 may beconnected to the bottom panel 56, the top edge of the inner wall 42 andthe top panel 54 may form a gap. As shown in FIGS. 10A and 10B, thecentrifuge media separator may have no inner wall 42. Regardless ofwhether the inner wall extends from the top panel 54 or the bottom panel56, the presence of an inner wall 42 will improve the efficiency of thecentrifuge media separator 30. That is, the higher the efficiency onlyincreasingly smaller particles will be returned to the dust collector.

The top panel 54, bottom panel 56, inner wall 42, and outer wall 40 maycollectively form an air passageway through which the blast media may bedrawn by a low pressure source 52 such as a blower mounted on the blastcabinet 10. The centrifuge media separator 30 is fluidly connected to aninterior 12 of the blast cabinet 10. The low pressure source 52 isfluidly connected to the central opening 36 and is configured to drawair into the inlet 34 and exhaust air through the central opening 36. Inthis manner, the blast media may be drawn upwardly from the interior 12and into the air passageway 32 wherein the blast particulate 18 may beseparated from the fine particulate 20. Optionally, a filter 22 may beprovided with the blast cabinet 10 to filter excess amounts of fineparticulate 20 leaving the air passageway 32 prior to exhaustion out ofthe blast cabinet 10. The blower may be mounted on the blast cabinet 10above the centrifuge media separator 30. The blower is configured toventilate the interior 12 by providing low pressure in an areasurrounding the centrifuge media separator 30. The low pressure providedby the blower draws spent portions of the blast media into thecentrifuge media separator 30 for subsequent separation into blastparticulate 18 and fine particulate 20.

The inlet 34 of the passageway may be rectangular shaped due to theorthogonal relation of the top and bottom panels 54, 56 and the outerwall 40. Similarly, the outlet 38 may also be partially rectangularshaped due to the orthogonal relation of the top and bottom panels 54,56, the outer wall 40 and inner wall 42. However, the inlet 34 may beconfigured in a variety of alternative shapes as may be provided byincluding an inlet 34 extension of, for example, cylindrical shape.Similarly, the outlet 38 configuration may be generally determined bythe shape of the upper and lower panels 54, 56 and the shape of theouter and inner walls 40, 42. The inlet 34 is configured to allow a flowof air to enter the air passageway 32 and circulate therethrough towardthe outlet 38.

As can be seen in FIGS. 2 and 5 , the air passageway 32 is preferablyconfigured such that a cross sectional area thereof generally decreasesalong a direction of the flow. Due to the truncated logarithmic spiralshape of the outer wall 40, and correspondingly, the passageway, theoutlet 38 is disposed radially inwardly relative to and positioneddownstream of the inlet 34 such that the flow of air enters the inlet34, circulates through the air passageway 32, exits the outlet 38, andrejoins the flow of air entering the inlet 34. The escape aperture 44 isconfigured to exhaust the blast particulate 18 out of the passageway.The central opening 36 is configured to exhaust the fine particulate 20out of the passageway when the low pressure source 52 is applied to anarea surrounding the central opening 36 in the top panel 54, as will bedescribed in greater detail below. The centrifuge media separator 30 maybe manufactured from material selected from the group consisting ofwood, plastic, metal, stainless steel, steel, or other suitable materialand any combination thereof.

The outer wall 40 may include at least one particulate escape aperture44 formed therein such that the blast particulate 18 may be exhaustedfrom the air passageway 32 for subsequent recycling through the blastcabinet 10. The escape aperture 44 may extend the entire height of theouter wall 40, may extend more than three quarters of the height of theouter wall 40, or more than half of the height of the outer wall 40. Thewidth of the escape aperture 44 may vary. By way of example and notlimitation, the escape aperture 44 may be as little as 1/64 inch orsmall and as much as 1¼ inch or larger. Other configurations are alsocontemplated.

The outer wall 40 may include an air foil 50 mounted thereon on adownstream side of the escape aperture 44. The air foil 50 may beconfigured to create a local area of high pressure adjacent the escapeaperture 44. The air foil 50 may vary aspects of the escape aperture 44.By way of example and not limitation, the air foil 50 may extend in tothe air passageway 32 to change the shape of the escape aperture 44, ormay change the width of the escape aperture 44, or both, as described indetail below.

As shown in FIGS. 3-7 , the air foil 50 may extend generally radiallyinwardly toward the central opening 36 and may span a distance betweenthe upper and lower panels 54, 56. More specifically, the air foil 50may be angled inwardly in a direction generally opposite that of adirection of flow from the inlet 34 to the outlet 38. The direction offlow into the inlet 34 and within the air passageway 32 is indicated inFIG. 2 by the arrow A. As shown in FIGS. 5-7 , the air foil 50 may beoriented at an angle of about forty-five degrees relative to a tangentof the outer wall 40 at a location from which the air foil 50 mayextend. However, it is contemplated that the air foil 50 may be providedin a variety of alternative configurations, including angles between 50and 55 degrees. Due to its shape and orientation in the air passageway32, the air foil 50 may be configured to facilitate exhaustion of theblast particulate 18 through the escape aperture 44. The air foil 50 maybe a separate component that is mounted on the outer wall 40.Alternatively, the air foil 50 may be integrally formed with the outerwall 40.

The air foil 50 may include a bracket 60, for example an angle bracket,attached to an outer surface 41 of the outer wall 40, a blade 35, andone or more mechanical fasteners 66. The bracket 60 may have twosections joined along an edge, forming a “V”-shaped transverse crosssection. The bracket 60 may be joined to the outer surface of the outerwall on a face of one of the two sections. Alternatively, the bracket 60may be joined to the outer surface of the outer wall along two free endsof the sections. The bracket 60 may be oriented at an angle of aboutforty-five degrees relative to a tangent of the outer wall 40 at alocation from which the bracket 60 may be attached. However, it iscontemplated that the bracket 60 may be provided in a variety ofalternative configurations. Additionally, the bracket 60 may be attachedto the outer wall 40, or top or bottom panels 54, 56.

The blade 35 may include a number of adjustment slots 62. The bracket 60may include the same number of holes 64. Using the adjustment slots 62and holes 64, the blade 35 may be fixed to the bracket 60 using the oneor more mechanical fasteners 66. The adjustment slots 62 may have afirst end 68 and a second end 70. As shown in FIG. 7 , when the blade 35is fixed to the bracket 60 with the one or more mechanical fasteners 66located at the first end 68, the blade 35 is at a minimum extension into the passageway 32. At the minimum extension, the blade 35 may directonly the blast particulate 18 with the greatest mass through the escapeaperture 44. As shown in FIG. 6 , when the blade 35 is fixed to thebracket 60 with the one or more mechanical fasteners 66 at the secondend 70, the blade 35 is at a maximum extension in to the passageway 32.The blade 35 may also be fixed to the bracket 60 at any point in betweenthe first end 68 and the second end 70 of the adjustment slots 62. Whenthe blade 35 is set at points beyond the minimum, the air foil 50 maydirect blast particulate 18 of decreasing mass through the escapeaperture 44, while still allowing the fine particulate 20 to continue tothe outlet 38.

The blade 35 may also include a leading edge 37 which is taperedrelative to front and rear faces of the blade 35. The taper on theleading edge 37 may help to create the area of high pressure adjacent tothe escape aperture 44. When the blade 35 is attached to the bracket 60using the mechanical fasteners 66, the taper on the leading edge 37 maypresent a relatively flat surface to the air flow as opposed to anangled surface. The taper may be created by a shorter front face of theblade and a longer rear faces of the blade 35.

The one or more mechanical fasteners 66 may create a friction connectionbetween the one or more fasteners 66, the blade 35, and the bracket 60,preventing the blade 35 from moving relative to the bracket 60. By wayof example and not limitation, the one or more mechanical fasteners 66may include a nut and bolt combination including various types of nuts,for example standard hexagonal nuts and wing nuts, or holding screwsthat engage threads on the angle bracket holes. Alternatively, the blade35 and bracket 60 may be attached by any removable means which preventthe blade 35 and bracket 60 from moving relative to one another.

Alternatively, as shown in FIGS. 8A, 8B, and 8C the air foil 50 mayinclude two sections, a base section 70 and a blade section 72. The basesection 70 may include adjustment slots 74. The adjustment slots 74 mayhave a longitudinal axis substantially parallel to a top edge and abottom edge of the outer wall 40. A mechanical fastener 66 may bedisposed in each of the adjustment slots 74. The each of the mechanicalfasteners 66 may attach to the outer wall 40 of the centrifuge mediaseparator 30. Alternatively, the mechanical fasteners 66 may passthrough both the adjustment slots 74 and the outer wall 40 and have twopieces which compress the base section 70 and outer wall 40 in betweenthe two pieces of the mechanical fastener 66. For example, themechanical fastener 66 may be a nut and bolt with the bolt on the insideof the outer wall 40 and the nut compressing against the base section70. The head of the bolt or nut may be disposed on the side of the bladesection 72 opposite the air flow, indicated by the arrows in FIG. 8A, inthe air passageway 32. The placement of the head of the bolt or nutbehind the blade section 72 prevents wear on the head of the bolt or nutfrom the impact of particles. The mechanical fasteners 66 may beloosened and the base section 70 moved so that the air foil 50 changesthe width of the escape aperture 44. Adjusting the width of the escapeaperture 44 changes the efficiency of the centrifuge media separator 30.Again, the narrower the escape aperture 44, the smaller the particlethat is sent to the dust collector.

The blade section 72 may form a common edge 76 with the base section 70.The blade section 72 may have a fixed width from the common edge 76 to afree edge 78 of the blade section 70. The fixed width means that theblade section 72 will extend to a fixed depth in the air passageway 32.

Because the blade 35 or the blade section 72 and base section 70 areremoveably attached, they may be replaced when they experience wear. Theability to replace worn blades 35 or air foil 50 with the blade section72 and base section 70 means that the centrifuge media separator 30 willnot experience a large drop in efficiency because of the wear to theparts.

Alternatively, there may be no air foil 50 in the escape aperture 44.The configuration including no air foil 50 may function well for lowefficiency applications with large, heavy abrasives. The escape aperture44 in this configuration may be from ¼ inch to 1.5 inches, with ¾ inchto 1 inch being preferred. The heavy abrasive may have enough momentumto continue on a path defined by a tangent to the curve of the outerwall 40 at the near side of the escape aperture 44. The curve of theouter wall 40 may allow the abrasive to pass through the escape aperture44 on the path of the tangent.

In use, the centrifuge media separator 30 may be attached to the bloweras mentioned above. The blower creates an area of low pressure adjacentthe central opening 36. The area of low pressure draws air into theinlet 34. As was earlier mentioned, the air contains a combination ofblast particulate 18 and fine particulate 20. Because the centrifugemedia separator 30 is configured such that the air passageway 32 circlesabout itself, particulate having a density greater than the air (i.e.,the blast particulate 18) tends to be centrifugally directed toward theouter wall 40. The blast particulate 18 may circulate within thecentrifuge media separator 30 in a sliding manner against the outer wall40.

When the blast particulate 18 reaches the escape aperture 44, the blastparticulate 18 may be directed to the escape aperture 44 by the air foil50, and exhausted from the air passageway 32. If no blast particulate 18is exhausted through the escape aperture 44, it may be because the blastparticulate 18 has a relatively lower mass, and is travelling in the airflow too far away from the outer wall 40 to be directed to the escapeaperture 44 by the air foil 50. The air foil 50, and specifically, theblade 35, may be adjusted by loosening the mechanical fasteners 66 andsliding the blade 35 to extend further in to the passageway 32, thenretightening the one or more mechanical fasteners 66. An air foil 50which extends further in to the passageway 32 will capture lower massblast particulate. A pressure differential may exist between an insideand outside of the air passageway 32 at an area adjacent the escapeaperture 44. As discussed above, the air foil may 50 extend in to theair passageway 32 some distance at an angle. When the air flowingthrough the air passageway 32 contacts the blade 35, the air will changedirection, and the change in direction will reduce the velocity of theair. The reduced velocity air will be at a pressure higher than the airin the air passageway 32 moving at a constant velocity or than air thatis accelerating in the air passageway 32. The air exterior to thepassageway 32 may have a lower pressure compared to that on the insideof the air passageway 32, and even lower than the air in the vicinity ofthe air foil 50, such that the blast particulate 18 is drawn to theoutside of the air passageway 32. Once outside of the air passageway 32,gravity may draw the blast particulate 18 downwardly into a blastparticulate hopper such that the blast particulate 18 can be reused.Thus, the pressure differential between the inside and outside of theair passageway 32 may be increased with the addition of the air foil 50such that the separating efficiency of the centrifuge media separator 30is enhanced. The ability to precisely adjust the air foil 50 allowsflexibility in the blast particulate 18 the blast cabinet 10 may use.

Downstream of the escape aperture 44, the air circulating through theair passageway 32 may contain fine particulate 20. The air with fineparticulate 20 may be drawn through the central opening 36 formed in theupper panel 54 due to the application of low pressure by the blower. Theair may pass under and around the inner wall 42 such that it may bedrawn upwardly through the central opening 36. The low pressure may besufficient to draw air with fine particulate 20 through the centralopening 36 but not insufficient to draw the blast particulate 18therethrough. As such, the blast particulate 18 downstream of the escapeaperture 44 may be recirculated through the air passageway 32 andredirected back to the inlet 34 such that the blast particulate 18 mightpass through the escape aperture 44.

The above description is given by way of example, and not limitation.Given the above disclosure, one skilled in the art could devisevariations that are within the scope and spirit of the inventiondisclosed herein, including various ways of attaching the blade to thebracket. Further, the various features of the embodiments disclosedherein can be used alone, or in varying combinations with each other andare not intended to be limited to the specific combination describedherein. Thus, the scope of the claims is not to be limited by theillustrated embodiments.

What is claimed is:
 1. A method of preparing a blast cabinet to be usedfor blasting the surface of a workpiece with blast particulate, themethod comprising: providing a blast cabinet having a housing, blastparticulate placed within the housing, and a centrifuge media separator,the centrifuge media separator including a top panel, a bottom panel, aninner wall extending downwardly from the top panel, an outer wallsurrounding the inner wall and extending between the top and bottompanels, and an escape aperture in the outer wall, the outer walldefining a truncated logarithmic spiral, the top panel, the bottompanel, the inner wall, and the outer wall collectively defining apassageway and a central opening, the passageway having an inlet and anoutlet and a transverse cross section which generally decreases from theinlet to the outlet; providing an air foil adjacent the escape aperture,the air foil extending inwardly toward the central opening and angled ina direction opposite a direction of airflow through the passageway, theair foil including a blade having a leading edge that is taperedrelative to front and rear faces of the blade so as to present a surfacethat faces the airflow; and adjusting a distance that the air foilextends from the outer wall into the passageway according to acorrelation between the distance and the mass of the blast particulate;wherein the blade includes at least one adjustment slot and the airfoilincludes a bracket attached to an outer surface of the outer wall,wherein the blade is attached to the bracket by mechanical fastenersthrough the at least one adjustment slot to allow the distance of theblade extending into the passageway to be adjusted along the slot. 2.The method of claim 1, wherein the at least one adjustment slot includesa gasket on an interior.
 3. The method of claim 1, further comprisingproviding a low pressure source mounted on the blast cabinet, the lowpressure source being fluidly connected to the central opening andconfigured to draw air into the inlet and exhaust air through thecentral opening.
 4. A method of preparing a blast cabinet to be used forblasting the surface of a workpiece with blast particulate, the methodcomprising: providing a blast cabinet having a housing and a centrifugemedia separator, the centrifuge media separator including a top panel, abottom panel, an inner wall extending downwardly from the top panel, anouter wall surrounding the inner wall and extending between the top andbottom panels, and an escape aperture in the outer wall, the outer walldefining a truncated logarithmic spiral, the top panel, the bottompanel, the inner wall, and the outer wall collectively defining apassageway and a central opening, the passageway having an inlet and anoutlet and a transverse cross section which generally decreases from theinlet to the outlet; providing an air foil adjacent the escape aperture,the air foil extending inwardly toward the central opening and angled ina direction opposite a direction of airflow through the passageway, theair foil including a blade having a leading edge that is taperedrelative to front and rear faces of the blade so as to present a surfacethat faces the airflow; adjusting a distance that the air foil extendsfrom the outer wall into the passageway according to a correlationbetween the distance and a mass of blast particulate; and placing theblast particulate within the housing; wherein the blade includes atleast one adjustment slot and the airfoil includes a bracket attached toan outer surface of the outer wall, wherein the blade is attached to thebracket by mechanical fasteners through the at least one adjustment slotto allow the distance of the blade extending into the passageway to beadjusted along the slot.
 5. The method of claim 4, wherein the at leastone adjustment slot includes a gasket on an interior.
 6. The method ofclaim 4, further comprising providing a low pressure source mounted onthe blast cabinet, the low pressure source being fluidly connected tothe central opening and configured to draw air into the inlet andexhaust air through the central opening.
 7. A method of blasting thesurface of a workpiece with blast particulate, the method comprising:providing a blast cabinet having a housing, blast particulate placedwithin the housing, and a centrifuge media separator, the centrifugemedia separator including a top panel, a bottom panel, an inner wallextending downwardly from the top panel, an outer wall surrounding theinner wall and extending between the top and bottom panels, and anescape aperture in the outer wall, the outer wall defining a truncatedlogarithmic spiral, the top panel, the bottom panel, the inner wall, andthe outer wall collectively defining a passageway and a central opening,the passageway having an inlet and an outlet and a transverse crosssection which generally decreases from the inlet to the outlet;providing an air foil adjacent the escape aperture, the air foilextending inwardly toward the central opening and angled in a directionopposite a direction of airflow through the passageway, the air foilincluding a blade having a leading edge that is tapered relative tofront and rear faces of the blade so as to present a surface that facesthe airflow; adjusting a distance that the air foil extends from theouter wall into the passageway according to a correlation between thedistance and the mass of the blast particulate; and blasting the surfaceof the workpiece with the blast particulate; wherein the blade includesat least one adjustment slot and the airfoil includes a bracket attachedto an outer surface of the outer wall, wherein the blade is attached tothe bracket by mechanical fasteners through the at least one adjustmentslot to allow the distance of the blade extending into the passageway tobe adjusted along the slot.
 8. The method of claim 7, wherein the atleast one adjustment slot includes a gasket on an interior.
 9. Themethod of claim 7, further comprising providing a low pressure sourcemounted on the blast cabinet, the low pressure source being fluidlyconnected to the central opening and configured to draw air into theinlet and exhaust air through the central opening.